Surgery has become increasingly less invasive thanks to advances in medical technology. Laparoscopy is the dominant minimally invasive surgical (MIS) approach used today and has replaced many traditional “open” approaches. In laparoscopic surgery, trocars (typically 3-5) are placed at separate points in the surgical field. These trocars serve as ports into a body cavity or other surgical space (such as the abdomen) through which special long and thin instruments can be inserted. Manipulation of these tools from outside the body mechanically translates into motion within the body cavity. Depending on the tool head design, different instruments have different functions. The appropriate instrument is selected based on what the surgeon needs for that step of the procedure.
Minimally Invasive Surgery (MIS) offers several advantages compared to open surgical procedures including minimal trauma to the abdominal wall and hence less postoperative pain, fewer wound complications, earlier patient mobilization, and shorter length of stay. Laparoscopic access to the peritoneal space is the dominant MIS approach when performing minimally invasive abdominal operations.
Recent clinical studies show that further reduction of the size and/or number of incisions may offer added benefits such as faster recovery, less pain, reduced operative time, and improved cosmetic result. Such benefits may have physical and psychological impact.
However, the size of the tool tips on conventional instruments used in laparoscopic procedures generally limit the ability to reduce the size of the incisions and trocars needed for such procedures.
Recent waves of scar-free techniques, including natural orifice trans-luminal endoscopic surgery (“NOTES”) and single-port surgery, have emerged to meet the need to further reduce the incisions required for surgical procedures. Ample information explaining the details of these new approaches exists in the public domain. Of the two, single-port surgery is thought among the surgery community to be the more feasible approach given available technology today.
Single-port surgery involves a multi-channel port that is typically placed in the belly button. This results in hidden scar post operatively. Through these channels, standard laparoscopic tools can be inserted. However, manipulation is more challenging because the tight aperture of the belly button and strong connective tissue in the abdominal wall forces all the instruments to move dependent on one another. In addition, the surgeon's hands are crowded together because of these constraints. Triangulation is largely lost. This makes the procedure frustrating to perform compared to other approaches.
A number of commercially available tools have been designed to circumvent some of these limitations. Some are variations of standard laparoscopic instruments but have articulating tool heads. Such designs are intended for re-enabling triangulation. However, constraints of the belly button port may force these articulating tools to cross, thus reversing the left-right motion between what the surgeon does with his hands and what he sees on the video monitor. Also, the complex mechanics behind the articulation may drive the cost up significantly.
The need exists for a revised laparoscopic technique and tools that reduce surgery-induced trauma but preserve the ergonomics and visualization to which surgeons have become accustomed. Such a procedure and tools may be safer for patients. A scar-free or minimal scar result may also appeal more to young adults, and the potential health benefits of a less traumatic approach may be higher for children and the elderly.
The first step during a laparoscopic surgical procedure is to insufflate the body cavity with a harmless gas (such as carbon dioxide) to increase the working space for the tools. The trocars are inserted across the abdominal wall and are designed to prevent excessive leakage of the insufflation gas, which invariably happens with incisions greater than three millimeters (3 mm).
In endoscopic and laparoscopic surgical procedures, a trocar device is used to puncture the patient's body in order to provide an access port through the abdominal wall to allow for the introduction of surgical instruments. A typical trocar requires a one-centimeter incision. Typically, a first trocar is placed above the umbilicus to introduce a camera to allow the surgeons to view the surgical site. The camera view is projected on a screen outside the body, which the surgeon and his or her assistants watch in order to appropriately manipulate the instruments inside the body cavity. Additional trocars are used to introduce surgical instruments, such as grasping tools, scissors, clips, and electrosurgical instruments. Typically, the laparoscopic instruments extend toward the surgical target from either side of the video camera. This “triangulation” of the instruments provides the most ergonomic and intuitive set up for the surgeon.
Patients who undergo laparoscopic surgery may benefit from shorter hospital stays and reduced surgery-inflicted morbidity compared to those who undergo open surgery. But, the number of trocar ports used in an operation is trauma-limited. For many cases, surgeries requiring more than five to seven (5-7) ports may be better performed using an open approach. Surgeons often hesitate to place more ports, even if it would mean making the procedure easier to do, because of the increased risk of wound complications with each additional incision (such as infection, dehiscence, or hernia).